If they're not already in electronic form, put them into electronic form.... MS Word would be one way to do that. That way you can keep them online or in your computer (backup!), then print out copies as needed.
Since my background is more based around live performances, my first inclination would be to make a setlist.... pick 5 or 6 songs that go well together that you enjoy playing, and focus on those first and foremost. That way you can put all of those songs together, in order, for easy reference.
By that method of organization, you could end up with three or four different "sets" as time goes by.... this prepares you for actual live performance (the key to pulling it off live? learn it so well that you can do it in your sleep!) and focuses your attention on a few songs at a time. When you can make your way through one "set" then you can start thinking about creating another one, ie another 5 or 6 songs - they don't all have to be new, you can mix and match, as long as you keep it interesting and follow a basic overall consistency in terms of mood/feel.
I strongly recommend printing them out and putting them in a binder of some kind, at the very least.
Another thought is to organize your songs in priority categories.... "A" being songs you really like and want to learn right away, "B" songs being songs you like and want to learn soon, and "C" songs that you want to learn at some point in time.
And it helps to practice your material a little more often. =)
Saul